Implement resource pack send event. (#625)

api/src/main/java/com/velocitypowered/api/event/player/ServerResourcePackSendEvent.java

@@ -0,0 +1,70 @@
+/*
+ * Copyright (C) 2018 Velocity Contributors
+ *
+ * The Velocity API is licensed under the terms of the MIT License. For more details,
+ * reference the LICENSE file in the api top-level directory.
+ */
+
+package com.velocitypowered.api.event.player;
+
+import com.velocitypowered.api.event.ResultedEvent;
+import com.velocitypowered.api.event.annotation.AwaitingEvent;
+import com.velocitypowered.api.proxy.ServerConnection;
+import com.velocitypowered.api.proxy.player.ResourcePackInfo;
+
+/**
+ * This event is fired when the downstream server tries to send a player a ResourcePack packet.
+ * The proxy will wait on this event to finish before forwarding the resource pack to the user.
+ * If this event is denied, it will retroactively send a DENIED status to the downstream
+ * server in response.
+ * If the downstream server has it set to "forced" it will forcefully disconnect the user.
+ */
+@AwaitingEvent
+public class ServerResourcePackSendEvent implements ResultedEvent<ResultedEvent.GenericResult> {
+  private GenericResult result;
+  private final ResourcePackInfo receivedResourcePack;
+  private ResourcePackInfo providedResourcePack;
+  private final ServerConnection serverConnection;
+
+  /**
+   * Constructs a new ServerResourcePackSendEvent.
+   * 
+   * @param receivedResourcePack The resource pack the server sent.
+   * @param serverConnection The connection this occurred on.
+   */
+  public ServerResourcePackSendEvent(
+      ResourcePackInfo receivedResourcePack,
+      ServerConnection serverConnection
+  ) {
+    this.result = ResultedEvent.GenericResult.allowed();
+    this.receivedResourcePack = receivedResourcePack;
+    this.serverConnection = serverConnection;
+    this.providedResourcePack = receivedResourcePack;
+  }
+
+  public ServerConnection getServerConnection() {
+    return serverConnection;
+  }
+
+  public ResourcePackInfo getReceivedResourcePack() {
+    return receivedResourcePack;
+  }
+
+  public ResourcePackInfo getProvidedResourcePack() {
+    return providedResourcePack;
+  }
+
+  public void setProvidedResourcePack(ResourcePackInfo providedResourcePack) {
+    this.providedResourcePack = providedResourcePack;
+  }
+
+  @Override
+  public GenericResult getResult() {
+    return this.result;
+  }
+
+  @Override
+  public void setResult(GenericResult result) {
+    this.result = result;
+  }
+}

api/src/main/java/com/velocitypowered/api/proxy/player/ResourcePackInfo.java

@@ -46,12 +46,48 @@ public interface ResourcePackInfo {
   byte[] getHash();
 
   /**
-   * Gets the {@link Origin} of the resource-pack.
+   * Gets the {@link Origin} of this resource-pack.
    *
    * @return the origin of the resource pack
    */
   Origin getOrigin();
 
+  /**
+   * Gets the original {@link Origin} of the resource-pack.
+   * The original origin may differ if the resource pack was altered in the event
+   * {@link com.velocitypowered.api.event.player.ServerResourcePackSendEvent}.
+   *
+   * @return the origin of the resource pack
+   */
+  Origin getOriginalOrigin();
+
+  /**
+   * Returns a copy of this {@link ResourcePackInfo} instance as a builder so that it can
+   * be modified.
+   * It is <b>not</b> guaranteed that
+   * {@code resourcePackInfo.asBuilder().build().equals(resourcePackInfo)} is true. That is due to
+   * the transient {@link ResourcePackInfo#getOrigin()} and
+   * {@link ResourcePackInfo#getOriginalOrigin()} fields.
+   *
+   *
+   * @return a content-copy of this instance as a {@link ResourcePackInfo.Builder}
+   */
+  ResourcePackInfo.Builder asBuilder();
+
+  /**
+   * Returns a copy of this {@link ResourcePackInfo} instance as a builder with the new URL as the pack URL so that
+   * it can be modified.
+   * It is <b>not</b> guaranteed that
+   * {@code resourcePackInfo.asBuilder(resourcePackInfo.getUrl()).build().equals(resourcePackInfo)} is true.
+   * That is due to the transient {@link ResourcePackInfo#getOrigin()} and
+   * {@link ResourcePackInfo#getOriginalOrigin()} fields.
+   *
+   * @param newUrl The new URL to use in the updated builder.
+   *
+   * @return a content-copy of this instance as a {@link ResourcePackInfo.Builder}
+   */
+  ResourcePackInfo.Builder asBuilder(String newUrl);
+
   interface Builder {
 
     /**